Spider Mite

Tetranychus urticae

Spider mites are not insects but arachnids related to spiders and ticks. Tetranychus urticae (the two-spotted spider mite) is the most common species on houseplants, though the red form and Panonychus ulmi (European red mite) are also encountered. They thrive in conditions above 25°C with low humidity, completing their entire life cycle in as little as 7 days. A single female can lay 200 eggs in her lifetime, making populations explode rapidly.

MonsteraCalatheaPhilodendronPothosFiddle Leaf Fig

How to Identify

Individual mites are barely visible to the naked eye (0.3–0.5 mm), appearing as tiny moving dots on leaf undersides. The first visible sign is usually fine, silvery stippling on the upper leaf surface — each dot is a cell emptied by mite feeding. Fine silk webbing between leaves and stems appears as populations grow. Hold a white sheet of paper under the plant and tap — if tiny specks fall and move, mites are present.

Life Cycle

Eggs hatch in 3–5 days at 25°C. The larva passes through two nymph stages before becoming adult, completing the cycle in 5–20 days depending on temperature. Hot, dry conditions accelerate reproduction dramatically — at 30°C, a population can double every 3 days. Cool, humid conditions below 60% RH slow reproduction.

Visual Identification

Webbing on Leaf

Mite Close-up

Stippled Leaf Damage

Treatment Steps

1
Isolate the affected plant — mites spread on air currents and through contact
2
Rinse all leaf surfaces with a strong water spray to physically remove mites and webbing
3
Apply neem oil (5 ml/L) or insecticidal soap to all plant surfaces, focusing on leaf undersides
4
Use a specific miticide (abamectin or bifenazate) for severe infestations — rotate products to prevent resistance
5
Introduce Phytoseiulus persimilis predatory mites for biological control in persistent cases
6
Repeat treatment every 5 days for 4–6 cycles to break the reproductive cycle

Prevention

Maintain humidity above 60% — spider mites cannot reproduce effectively in humid conditions
Clean leaves regularly with a damp cloth to remove eggs and early colonies
Avoid placing plants near heating vents or in hot, dry locations
Quarantine all new plants for 2–3 weeks before placing near existing plants

Frequently Asked Questions

How do I know if I have spider mites?

Hold a white sheet under the plant and tap the leaves. If tiny moving specks fall onto the paper, you have spider mites. Stippled silver dots on leaf surfaces and fine webbing between leaves and stems are also definitive signs.

What kills spider mites instantly?

Isopropyl alcohol (70%) applied directly to mites kills them on contact. Neem oil and insecticidal soap are effective for spraying large areas. For instant knockdown of heavy infestations, a miticide containing abamectin or bifenazate is most reliable.

Why do spider mites keep coming back?

Spider mites lay up to 200 eggs, which resist many treatments. Returning populations usually come from eggs that survived the last treatment. You must repeat treatment every 5 days for at least 4–6 cycles to intercept newly hatched nymphs before they can reproduce.

Do spider mites live in soil?

Two-spotted spider mites (Tetranychus urticae) live primarily on leaf surfaces. However, some mite species do overwinter in soil. If mites return after thorough foliar treatment, examine the soil surface and top-dress with fresh substrate.